U.S. patent number 7,066,924 [Application Number 09/200,055] was granted by the patent office on 2006-06-27 for method of and apparatus for navigating medical devices in body lumens by a guide wire with a magnetic tip.
This patent grant is currently assigned to Stereotaxis, Inc.. Invention is credited to Walter M. Blume, Jeffrey M. Garibaldi.
United States Patent |
7,066,924 |
Garibaldi , et al. |
June 27, 2006 |
Method of and apparatus for navigating medical devices in body
lumens by a guide wire with a magnetic tip
Abstract
A guide wire combined with a catheter or medical device for
moving through a body lumen to a desired position in the body with
the aid of an applied magnetic field. The guide wire is provided
with a magnet on its distal end that can be oriented or oriented
and moved by the application of a magnetic field to the magnet. A
catheter or other medical device can be advanced over the guide
wire. Once the medical device is in its desired position, the
magnet can be withdrawn through the lumen of the catheter.
Alternatively, a guide wire with a magnet on its distal end can be
docked at the distal end of a catheter or medical device and can be
oriented, or oriented and moved by the application of a magnetic
field.
Inventors: |
Garibaldi; Jeffrey M. (St.
Louis, MO), Blume; Walter M. (Webster Groves, MO) |
Assignee: |
Stereotaxis, Inc. (St. Louis,
MO)
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Family
ID: |
36600387 |
Appl.
No.: |
09/200,055 |
Filed: |
November 25, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/US98/02835 |
Feb 17, 1998 |
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08969165 |
Aug 3, 1999 |
5931818 |
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Current U.S.
Class: |
604/510;
604/164.13 |
Current CPC
Class: |
A61M
25/0127 (20130101); A61M 25/09 (20130101); A61M
2025/09075 (20130101); A61M 2025/09083 (20130101) |
Current International
Class: |
A61M
31/00 (20060101) |
Field of
Search: |
;600/11,12,431,433,439,585 ;604/95,164,270 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lucchesi; Nicholas
Assistant Examiner: Ahmed; Aamer
Attorney, Agent or Firm: Harness Dickey & Pierce PLC
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation in part of PCT application Ser.
No. PCT/US98/02835 filed Feb. 17, 1998 and is a continuation in
part of U.S. application Ser. No. 08/969,165 filed Nov. 12, 1997
and issued Aug. 3, 1999 as U.S. Pat. No. 5,931,818.
Claims
What is claimed is:
1. A wire for use in navigating a medical device through a body
lumen to a particular location, the guide wire having a proximal
end and a distal end, and a magnet on the distal end, the guide
wire being sufficiently flexible adjacent the magnet to allow the
wire to flex in response to a magnetic field applied to the magnet,
yet the wire being sufficiently stiff to allow the wire to be
advanced through the body lumen; wherein the magnet on the distal
end comprises a flexible magnetic material forming a distal end
section of the guide wire.
2. In combination with a medical device having a proximal end, a
distal end, and a lumen therebetween, a guide wire having a
proximal end, a distal end, and a magnet on the distal end, the
guide wire extending through the lumen of the medical device, with
the distal end of the guide wire extending beyond the distal end of
the medical device; wherein the magnet on the distal end comprises
a flexible magnetic material forming a distal end section of the
guide wire.
3. A method of navigating a medical device through a body lumen to
a desired location within the body, the method comprising:
providing a medical device having a lumen therethrough, the lumen
having a proximal end and a distal end; inserting a guide wire
having a proximal end and a magnetic distal tip, the distal tip of
the guide wire being made from a flexible magnetic material,
through the lumen of the device until at least a portion of the
magnetic distal tip extends distally beyond the distal end of the
lumen in the medical device; inserting the medical device and the
guide wire into a lumen in the body; navigating the medical device
through the lumen in the body by applying a magnetic field to
orient the magnetic tip in the desired direction of travel;
advancing the guide wire in the direction in which the magnetic tip
is oriented; and advancing the medical device over the guide wire;
wherein the magnetic tip of the guide wire comprises a distal
section of the guide wire being made from a flexible magnetic
material.
4. The method according to claim 3, wherein the step of navigating
the medical device comprises successively incrementally advancing
the guide wire and the medical device.
5. A method of navigating a medical device through a body lumen to
a desired location within the body, the method comprising:
providing a medical device having a lumen therethrough, the lumen
having a proximal end and a distal end; inserting a guide wire,
having proximal end and a magnetic distal tip comprising a
plurality of magnets secured on the distal end section of the guide
wire in spaced apart relation allowing the guide wire to assume a
shape under control of the magnetic field, through the lumen of the
device until at least a portion of the magnetic distal tip extends
distally beyond the distal end of the lumen in the medical device;
inserting the medical device and guide wire into a lumen in the
body; navigating the medical device through the lumen in the body
by applying a magnetic field to shape the magnetic distal tip in
the desired configuration to the orient the magnetic tip in the
desired direction of travel; advancing the guide wire in the
direction in which the magnetic tip is oriented; and advancing the
medical device over the guide wire.
6. The method according to claim 5, wherein the step of navigating
the medical device comprises successively incrementally advancing
the guide wire and the medical device.
7. In combination with a guide wire having a proximal end, a distal
end, and a magnetic distal tip, a medical device having a proximal
end, a distal end, and a lumen extending substantially to the
distal end of the device, the guide wire extending into the lumen
of the medical device with the magnetic distal tip in the distal
end of the lumen in the medical device; wherein a distal end
portion of the guide wire is sufficiently flexible to allow the
magnetic tip to move in response to an applied magnetic field, but
a proximal section of the guide wire is sufficiently stiff to
advance the medical device through a lumen in the body; and wherein
the magnetic distal tip comprises a flexible magnetic material
forming a distal end section of the guide wire.
8. The combination according to claim 7 wherein the lumen of the
medical device has a stricture therein for engaging the guide wire
and retaining the guide wire in the lumen of the medical
device.
9. In combination with a guide wire having a proximal end, a distal
end, and a magnetic distal tip, the magnetic distal tip comprises a
plurality of magnets on the distal end section of the guide wire in
spaced apart relation, the portion of the guide wire adjacent the
distal end being sufficiently flexible to allow the magnetic tip to
move in response to an applied magnetic field, but the proximal
section of the guide wire being sufficiently stiff to advance a
medical device through a lumen in the body, a medical device having
proximal end, a distal end, and a lumen extending substantially to
the distal end of the device, the guide wire extending into the
lumen of the medical device with the magnetic distal tip in the
distal end of the lumen in the medical device.
10. The combination according to claim 9 wherein the lumen of the
medical device has a stricture therein for engaging the guide wire
and retaining the guide wire in the lumen of the medical
device.
11. A method of navigating a medical device through a body lumen to
a desired location within the body, the method comprising:
providing a medical device having a proximal end; a distal end, and
a lumen extending to substantially the distal end of the medical
device; inserting a guide wire having a proximal end and a magnetic
distal tip into the lumen until the magnetic tip is substantially
adjacent the distal end of the medical device, the magnetic tip of
the guide wire comprises a plurality of magnets secured on the
distal end section of the guide wire in spaced apart relation;
inserting the medical device and the guide wire into a lumen in the
body; navigating the medical device through the lumen in the body
by applying a magnetic field to orient the magnetic tip inside the
lumen of the medical device so that the distal end of the medical
device is oriented in the desired direction of travel; and
advancing the guide wire and medical device in the direction in
which the distal end of the medical device is oriented.
12. The method according to claim 11 wherein the magnetic tip
comprises a permeable magnetic material.
13. The method according to claim 11 wherein the magnetic tip
comprises a permanent magnetic material.
14. The method according to claim 11, wherein the step of
navigating the medical device comprises successively orienting and
advancing the guide wire and medical device.
Description
FIELD OF THE INVENTION
This invention relates to a method of, and apparatus for,
navigating medical devices in body lumens, such as in blood
vessels, the trachea, the gastrointestinal tract, or the urinary
tract.
BACKGROUND OF THE INVENTION
Many diagnostic and therapeutic medical procedures require
navigating a medical device to a particular location through lumens
in the body. For example, procedures such as cardiac
catheterizations and interventional neuroradiology procedures
involve the introduction of medical devices through the arteries;
bronchoscopies involve the introduction of medical devices through
the trachea; endoscopies and colonoscopies involve the introduction
of instruments through the gastrointestinal tract; and
urethroscopies involve the introduction of medical devices through
the urinary tract.
Numerous methods and apparatus have been developed for introducing
medical devices in the body. Many of these methods employ guide
wires for remotely controlling the orientation of the tip of the
medical device as it is advanced in the body lumen. These guide
wires typically have a bend in their distal ends, the tip is
rotated until the tip is properly oriented, and the wire is then
advanced. It is a difficult and tedious process to steer a medical
device remotely with a guide wire since the orientation of the
guide wire is difficult to control. Thus, these procedures can be
prolonged, which increases the risk to the patient and fatigues the
physician.
It has been proposed to guide medical devices in the body with
magnets, see Yodh, Pierce, Weggel, and Montgomery, A New Magnetic
System, for `Intravascular Navigation`, Medical & Biological
Engineering, Vol. 6, No. 2, pp. 143 147 (March 1968), incorporated
herein by reference. This article proposes a magnetically tipped
catheter that is steered within the body by an externally applied
magnetic field. However, the magnet in this proposed device is
attached to the catheter which can impair the ability to control
the magnet. Moreover, there is no provision for removing the magnet
and leaving the catheter or other medical device in place. Thus,
only one such catheter can be directed to a given position because
the magnetic field acting on one magnet will also act on the other
magnets in the vicinity.
SUMMARY OF THE INVENTION
The methods and apparatuses of the present invention involve
magnetically guiding a medical device through a lumen in the body.
Generally, according to the method of this invention, a magnet is
provided on the end of a guide wire and an externally applied
magnetic field orients the magnet in the body lumen. The magnet can
be advanced through the body lumen by manipulating the magnetic
field or by pushing the guide wire.
According to a first embodiment of this invention, a catheter may
be disposed over a guide wire having a magnet on its distal end.
The guide wire and catheter combination is introduced into a body
lumen through a natural or surgically formed opening. Once in the
body the guide wire and catheter combination is navigated through
the body lumen by applying a magnetic field, which acts on the
distal end of the guide wire, orienting it. Typically, the guide
wire is advanced slightly ahead of the catheter at a branch in the
body lumen, and a magnetic field is applied to orient the tip of
the guide wire, and the guide wire is advanced in the direction of
the tip which is oriented into the selected branch. The guide wire
can be advanced by the application of the magnetic field, by
pushing at the proximal end, or by both. The catheter is then
advanced over the guide wire. This process is repeated until the
distal end of the catheter is at its desired location. Once the
distal end of the catheter is in the desired position, the magnet
can be withdrawn through the lumen of the catheter by pulling on
the tether. Treatment, such as drug therapy or embolizing agents,
can then be passed through the catheter.
According to a second embodiment of this invention, a guide wire
with a magnet on the tip may be docked at the distal end of the
lumen inside a catheter or other medical device. The guide wire and
catheter combination is introduced into a body lumen through a
natural or surgically formed opening. Once in the body lumen, the
guide wire and catheter combination is navigated through the body
lumen by applying a magnetic field, which acts upon the
magnet-tipped guide wire in the catheter, orienting it. The
catheter is advanced by pushing the guide wire. Once the distal end
of the catheter is in the desired location, the guide wire can be
withdrawn through the lumen of the catheter by pulling on the guide
wire. Treatment, such as drug therapy or embolizing agents, can
then be passed through the catheter.
The methods of the various embodiments of this invention, and the
guide wire of the various embodiments of this invention, facilitate
quick, easy and accurate positioning of a catheter or other medical
device via a body lumen. Once the catheter is properly positioned,
it can be used during a diagnostic or therapeutic procedure, either
directly or as a passage for other medical devices.
These and other features and advantages will be in part apparent
and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross-sectional view of a guide wire and
catheter combination constructed according to the principles of a
first embodiment this invention;
FIG. 2 is a plan view of the guide wire of the first
embodiment;
FIG. 3 is an enlarged cross-sectional view of the distal tip of the
guide wire;
FIG. 4 is an enlarged cross sectional view the distal end of a
first alternate construction of the guide wire of the first
embodiment, using a socket to secure the magnet;
FIG. 5 is an enlarged cross sectional view of the distal end of a
second alternate construction of the guide wire of the first
embodiment, using a collar to secure the magnet.
FIG. 6 is an enlarged cross-sectional view of a third alternate
construction of the distal section of the guide wire;
FIG. 7 is an enlarged cross-sectional view of a fourth alternate
construction of the distal section of the guide wire;
FIG. 8 is a side elevation view of the distal section of a fifth
alternate construction of the guide wire of the first embodiment
with a portion broken away to show details of the construction;
FIG. 9 is a side elevation view of the distal end section of a
sixth alternate construction of the guide wire of the first
embodiment;
FIG. 10 is a side elevation view of the distal end section of a
seventh alternate construction of the guide wire of the first
embodiment;
FIG. 11 is a side elevation view of the distal section of an eighth
alternate construction of the guide wire of the first
embodiment;
FIG. 11a is an enlarged side elevation view of the eighth alternate
construction of the distal end section, with a portion broken away
to show details of the construction;
FIG. 12 is a side elevation view of the distal section of a ninth
alternate construction of the guide wire of the first
embodiment;
FIG. 12a is a side elevation view of the distal section of the
ninth alternate construction of the guide wire, in a magnetic
field;
FIG. 13 is a side elevation view of a tenth alternate construction
of the distal section of the guide wire;
FIG. 13a is a side elevation view of a tenth alternate construction
of the distal tip of the guide wire, in a magnetic field;
FIG. 14 is a longitudinal cross-sectional view of the guide wire
and endoscope combination constructed according to the principles
of the first embodiment of this invention;
FIG. 15 is a longitudinal cross-sectional view of a guide wire and
catheter combination according a second embodiment of this
invention;
FIG. 16 is a longitudinal cross-sectional view of a guide wire and
catheter combination with the guide wire partially withdrawn from
the lumen of the catheter; and
FIG. 17 is a side elevation view of a guide wire and biopsy device
according to the principles of the present invention.
Corresponding reference numbers indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A guide wire and magnet combination constructed according to the
principles of a first embodiment of this invention is indicated
generally as 20 in FIG. 1. The guide wire and catheter combination
20 comprises a guide wire 22 and a catheter 24. The guide wire 22
comprises a wire 26, which is preferably made of nitinol, which is
highly flexible and resists kinking, although the guide wire could
be made of some other suitable material. A magnet 28 is mounted on
the distal end 30 of the wire 26. This magnet may either be a
permanent magnet or a permeable magnetic material. A permanent
magnet is easier to orient under the application of a magnetic
field, as described below, but a permeable magnetic material is
easier to pull under the application of a magnetic field.
In the preferred embodiment, the magnet 28 is made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to orient the guide wire
22 in the body lumen and to be retracted through the catheter 24.
The magnet 28 is preferably elongate so that it can orient the tip
of the guide wire 22 in the presence of an applied magnetic field.
Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches)
in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches)
long are sufficiently large for use in navigating a guide wire.
As shown in FIGS. 2 and 3, the magnet 28 is preferably a
cylindrical body 34 with an axial bore 36 therethrough. The distal
end of the wire 26 extends through the bore 36, and is secured with
a bead 38 of adhesive on the distal side of the magnet 28. The bead
38 also provides a rounded head on the distal end 30 of the guide
wire 22.
A first alternate construction of the guide wire 22 of the first
embodiment is indicated generally as 40 in FIG. 4. The guide wire
40 is similar in construction to guide wire 22, comprising wire 42,
having a proximal end (not shown) and a distal end 44. A mounting
body 46, having a socket 48 therein, is attached to the distal end
44 of the wire. A magnet 50 is mounted in the mounting body. The
magnet can be secured in the mounting body with adhesive, or the
socket 48 can be crimped to secure the proximal end of the magnet
50 in the socket 48.
A second alternate construction of the guide wire 22 of the first
embodiment is indicated generally as 60 in FIG. 5. The guide wire
60 is similar in construction to guide 22, comprising a wire 62
having a proximal end (not shown) and a distal end 64. A mounting
collar 66 is attached to the distal end 64 of the wire 62. A magnet
68 is mounted on the mounting collar 66. The magnet 68 can be
secured to the mounting collar 66 by adhesive or by fusion.
A third alternate construction of the guide wire 22 is indicated
generally as 70 in FIG. 6. The guide wire 70 is similar in
construction to guide 22, comprising a wire 72 having a proximal
end (not shown) and a distal end 74, and a magnet 76 mounted on the
distal end of the wire 72. The magnet 76 is preferably a
cylindrical body with an axial bore 78 therethrough. The distal end
of the wire 24 extends through the bore 78, and is secured with a
bead 80 of adhesive on the distal side of the magnet 76. The bead
80 also provides a rounded head on the distal end of the guide wire
22. There is a tapering collar 82 on the wire 26 proximal to the
magnet 76. The collar 82 facilitates withdrawing the magnet 76
through the distal end of the catheter 24. The collar can be made
of platinum or some other non-magnetic radio opaque material so
that the position of the end of the guide wire can be easily
located with x-ray or fluoroscopic imaging equipment.
A fourth alternative construction of a guide wire 22 is indicated
generally as 90 in FIG. 7. The guide wire 90 is similar in
construction to guide wire 22, comprising a wire 92 having a
proximal end (not shown) and a distal end 94, and a magnet 96 on
the distal end of the wire 92. The magnet 96 is preferably a
cylindrical body with an axial bore 98 therethrough. The distal end
of the wire 24 extends through the bore 98, and is secured with a
bead 100 of adhesive on the distal side of the magnet 96. The bead
100 also provides a rounded head on the distal end of the guide
wire 90. The guide wire 90 includes a sheath 102, made of flexible
polyurethane tubing, extending over the wire 92. The sheath 102
preferably has the same outside diameter as the magnet 96, to
smoothly slide in the lumen of the catheter, and to help prevent
excessive movement of the guide wire 90 within the lumen. The
sheath 102 is preferably secured to the proximal end of the magnet
96 with an adhesive, such as SICOMET 40 available from Tracon.
A fifth alternate construction of the guide wire of the first
embodiment is indicated generally as 110 in FIG. 8. Guide wire 110
comprises a wire 112 having a proximal end (not shown) and a distal
end 114. The wire 112 is preferably made of nitinol, which is
highly flexible and resists kinking, although it could be made of
some other suitable material. A magnet 116, which can either be a
permeable magnet or a permanent magnet, is secured on the distal
end 114. A permanent magnet is easier to orient under the
application of a magnetic field, as described below, but a
permeable magnetic material is easier to pull under the application
of a magnetic field.
The magnet 116 is preferably made of NdFeB (neodymium-iron-boron)
or samarium cobalt and is sized to respond to the magnetic field
that will be applied to orient the distal tip of the guide wire 110
in the body lumen and to be retracted through the lumen of the
catheter or other medical device. The magnet 116 is preferably
elongate so that it can orient the distal tip of the guide wire 110
in the presence of an applied magnetic field. Magnets of about 0.3
mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and
about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are
sufficiently large for use in navigating a guide wire.
As shown in FIG. 8, the magnet 116 is preferably a cylindrical
body. A magnetic or non-magnetic sleeve 118, made of a suitable
sheet material or wire, covers the magnet 116 and extends over the
distal end 114 of the guide wire 110, securing the magnet on the
wire. In this preferred embodiment shown in FIG. 8 the sleeve 118
is made from a thin plastic tube, which is can be secured over the
magnet and the distal end of the guide wire, with an adhesive, or
more preferably, by heat shrinking.
A sixth alternate construction of the guide wire of the first
embodiment is indicated generally as 120 in FIG. 9. Guide wire 120
comprises a wire 122 having a proximal end (not shown) and a distal
end 124. The wire 122 is preferably made of nitinol, which is
highly flexible and resists kinking, although it could be made of
some other suitable material. A magnet 126, which can either be a
permeable magnet or a permanent magnet, is secured on the distal
end 124, for example with adhesive. A permanent magnet is easier to
orient under the application of a magnetic field, as described
below, but a permeable magnetic material is easier to pull under
the application of a magnetic field.
The magnet 126 is preferably made of NdFeB (neodymium-iron-boron)
or samarium cobalt and is sized to respond to the magnetic field
that will be applied to orient the distal tip guide wire 120 in the
body lumen and to be retracted through the lumen of the catheter or
other medical device. The magnet 126 is preferably elongate so that
it can orient the distal tip of the guide wire 120 in the presence
of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches)
to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04
inches) to 1.5 mm (0.06 inches) long are sufficiently large for use
in navigating a guide wire.
As shown in FIG. 9, the magnet 126 is preferably a cylindrical
body. A sleeve 128, made of wire, covers the magnet 126 and extends
over the distal end 124 of the wire 122, helping to secure the
magnet on the wire. In this preferred embodiment shown in FIG. 9,
the sleeve 128 is a coil of platinum wire, the proximal end of
which is secured to the wire 122 proximal to the distal end 124,
and the distal end of which is secured to the magnet 126. The coil
improves the axial stiffness of the distal end while leaving the
guide wire flexible in other directions to permit magnetic
navigation. The coil also improves the radiopacity of the end of
the guide wire so that it can be seen on x-ray and fluoroscopic
images. The coil is secured to the wire 122 and to the magnet 126
with adhesive. The adhesive preferably fills the spaces between the
turns of the coil around the magnet 126, so that the surface is
smooth.
A seventh alternate construction of the guide wire of the first
embodiment is indicated generally as 130 in FIG. 10. Guide wire 130
comprises a wire 132 having a proximal end (not shown) and a distal
end 134. The wire 132 is preferably made of nitinol, which is
highly flexible and resists kinking, although it could be made of
some other suitable material. A magnet 136, which can either be a
permeable magnet or a permanent magnet, is secured on the distal
end 132, for example with adhesive. A permanent magnet is easier to
orient under the application of a magnetic field, as described
below, but a permeable magnetic material is easier to pull under
the application of a magnetic field.
The magnet 136 is preferably made of NdFeB (neodymium-iron-boron)
or samarium cobalt and is sized to respond to the magnetic field
that will be applied to orient the distal tip guide wire 130 in the
body lumen and to be retracted through the lumen of the catheter or
other medical device. The magnet 136 is preferably elongate so that
it can orient the distal tip of the guide wire 130 in the presence
of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches)
to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04
inches) to 1.5 mm (0.06 inches) long are sufficiently large for use
in navigating a guide wire.
As shown in FIG. 10, the magnet 136 is preferably a cylindrical
body. A coil 138 of platinum wire is disposed over the distal end
portion of the wire 132. The proximal end of the coil is attached
to the wire 132 proximal to the distal end, and the distal end of
the coil is attached to the proximal end of the magnet 136. The
coil improves the axial stiffness of the distal end while leaving
the guide wire flexible in other directions to permit magnetic
navigation. The coil also improves the radiopacity of the end of
the guide wire so that it can be seen on x-ray and fluoroscopic
images. The coil 98 is secured to the wire 92 and to the magnet 96
with adhesive. A sleeve 140 covers the magnet 136 and extends over
the coil 138 and the distal end 134 of the wire 130, helping to
secure the magnet and the coil on the wire. In this preferred
embodiment shown in FIG. 10, the sleeve 140 is a tube of a flexible
plastic material, that is secured with an adhesive, or more
preferably by heat shrinking.
An eighth alternate construction of the guide wire of the first
embodiment is indicated generally as 150 in FIGS. 11 and 11a. Guide
wire 150 comprises a wire 152, having a proximal end (not shown)
and a distal end 154. The wire 152 is preferably made of nitinol,
which is highly flexible and resists kinking, although it could be
made of some other suitable material. The wire 152 tapers toward
the distal end 154. The portion of the wire 152 adjacent the distal
end is surrounded by a magnetic coil 156.
A ninth alternate construction of the first embodiment of a guide
wire according to the principles of this invention is indicated
generally as 160 in FIGS. 12 and 12a. Guide wire 160 comprises a
wire 162 having a proximal end (not shown) and a distal end 164.
Instead of a single magnet on the distal end of the wire, as in the
first embodiment, guide wire 160 has a series of spaced magnets 166
on the distal end portion 168 of the wire 162. The magnets 166 each
preferably have a generally cylindrical body, with an axial bore
170 extending therethrough. The distal portion 54 of the wire 56
extends through the bores 60, and the magnets 52 are secured to the
wire 56 in spaced apart relation with adhesive.
The magnets 166 are preferably made from NdFeB, and have a diameter
of 2 mm (0.08 inches) and are 4 mm (0.16 inches) long. The magnets
166 are preferably spaced over the distal 5 cm (2 inches) of the
guide wire 160, and are spaced 1 cm (0.4 inches) on center. Of
course some other size magnets and/or different magnet spacing
could be used. Moreover the spacing of the magnets does not have to
be equal. This third alternate construction is particularly useful
for an electrophysiology catheter where the magnetic fields could
pull or shape the guide wire 160 to the heart wall, thereby guiding
the electrophysiology catheter over the guide wire against the
heart wall.
As shown in FIG. 12a, upon the application of a magnetic field, the
magnets 166 on the distal end portion 164 of the guide wire 160
cause the guide wire to assume a particular shape dictated by the
field. Thus by controlling the applied magnetic field, the shape of
the distal portion of the guide wire can be controlled,
facilitating the navigation through, or shaping to, the body lumen.
The guide wire 160 can be advanced by pulling with a magnetic force
on the magnets 166, or the proximal end can be manually pushed. A
magnetic pulling force could also be used to hold the catheter with
guide wire to the wall of a body lumen.
A tenth alternate construction of the first embodiment of a guide
wire constructed according to the principles of the present
invention is indicated generally as 180 in FIGS. 13 and 13a. The
guide wire 180 comprises a wire 182, having a proximal end (not
shown) and a distal end 184. Instead of the single magnet on the
distal end of the wire, or a plurality of magnets on the distal end
portion of the wire, the distal end portion 186 of guide wire 180
is made from a flexible magnetic material.
The distal end portion 186 is preferably about 0.25 mm (0.01
inches) in diameter, and about 1 cm (0.4 inches) long. The distal
end portion can be made of a permeable magnetic material such as a
steel or a magnetic stainless steel wire, or a steel or a magnetic
stainless steel braid.
As shown in FIG. 13a, upon the application of a magnetic field, the
distal end portion 186 of the guide wire 180 assumes a particular
orientation dictated by the field. Thus by controlling the applied
magnetic field, the orientation and/or shape of the distal portion
186 of the guide wire 180 can be controlled, facilitating the
navigation through the body lumen. The guide wire 180 can be
advanced by magnet force on the distal end portion 186, or the
proximal end can be pushed. The magnetic field can also function to
selectively stiffen the distal end portion 186 of the guide wire,
to facilitate navigation through the body lumen. This allows the
guide wire 182 to be designed with the minimum amount of stiffness
to overcome static friction when applying an axial pushing force on
at the proximal end. Sufficient stiffness for navigation can be
provided by applying a magnetic field to the distal tip.
As shown in FIG. 1, the catheter 24 is preferably of conventional
construction, having a proximal end 200, a distal end 202, and a
lumen 204 extending therebetween. The catheter 24 can be made of
polyurethane tubing, or some other suitable material. The size of
the catheter 24 depends upon where in the body it will be
introduced, and how it will be used. For example, for use in the
blood vessels in the brain, the catheter might have an outside
diameter of about 0.7 mm (0.03 inches), an inside diameter of about
0.6 mm (0.02 inches), and a length of about 2 m (6.6 feet). Of
course, medical devices other than catheters can be used with the
guide wire, for example an endoscope where the guide wire is
inserted through its working channel. These devices would typically
include a lumen extending all or partly along the length of the
device that passes over the guide wire so that the device follows
the guide wire.
One of the guide wires of the present invention can be introduced
into a body lumen, such as a blood vessel, and navigated to its
desired location by the controlled application of magnetic fields.
The application of a magnetic field allows the operator to steer
the distal end of the guide wire by orienting the distal end of the
guide wire to the desired direction of travel. The guide wire can
be advanced using the magnetic field to pull the magnet on the
distal end of the guide wire, or the guide wire can be advanced by
pushing the proximal end. As the guide wire advances, the catheter
24 or other medical device can be advanced over the guide wire,
until the catheter or medical device is in its desired
location.
Once the distal end 202 of the catheter 24 has been placed in its
desired location, the guide wire can be left in place, or if the
magnet is sufficiently small, the guide wire can be withdrawn
through the lumen 204 of the catheter and out the proximal end
200.
The magnetic articulation of the distal end of the guide wire
eliminates the need to provide a permanent bend in the guide wire
in order to navigate through branches in body lumens. The straight
configuration of the guide wires permitted by the present invention
permits faster and easier navigation in straight sections of the
body lumen and reduces unintentional diversion down branches of the
lumen.
As shown in FIG. 14, one of the guide wires of this invention can
be used to navigate an endoscope 300 through a body lumen, such as
a colon. The endoscope 300 has a lumen 302 extending therethrough.
A magnetic field is applied to orient the magnet on the distal end
of the guide wire with the magnetic field. The endoscope 300 can
then be advanced over the guide wire, the lumen 302 sliding over
the guide wire. The guide wire is preferably incrementally
advanced, and the endoscope is then advanced over the guide wire,
until the distal end of the endoscope 300 reaches its desired
location.
A guide wire and catheter combination constructed according to a
second embodiment of this invention is indicated generally as 400
in FIGS. 15 and 16. The guide wire and catheter combination 400
comprises guide wire 402 and catheter 404. The guide wire 402
comprises a wire 406, preferably made of nitinol, which is highly
flexible and resists kinking, although the guide wire could be made
of some other suitable material. A magnet 408 is mounted on the
distal end 410 of the wire 406. This magnet may either be a
permanent magnet or a permeable magnetic material. A permanent
magnet is easier to orient under the application of a magnetic
field, as described below, but a permeable magnetic material is
easier to pull under the application of a magnetic field.
In the preferred embodiment, the magnet 408 is made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to move the guide wire
402 through the body lumen. The magnet 408 is preferably elongate
so that it can orient the tip of the guide wire 402 in the presence
of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches)
to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04
inches) to 1.5 mm (0.06 inches) long are sufficiently large for use
in navigating a guide wire.
As shown in FIG. 16, the magnet is preferably a cylindrical body
with an axial bore 412 therethrough. The distal end of the wire 410
extends through the bore 412, and is secured with a bead 414 of
adhesive on the distal side of the magnet 408. The bead 414 also
provides a rounded head on the distal end of the guide wire 402. Of
course instead of magnet 408, the guide wire 402 could have a
plurality of spaced magnets on the distal end portion similar to
guide wire 160, described above, or the distal end portion of the
guide wire could be made of a flexible magnetic material similar to
guide wire 180.
The catheter 404 is preferably of conventional construction, having
a proximal end 416, a distal end 418, and a lumen 420 extending
therebetween. The catheter 404 can be made of polyurethane tubing,
or some other suitable material. The size of the catheter 404
depends upon where in the body it will be introduced, and how it
will be used. For example, for use in the blood vessels in the
brain, the catheter might have an outside diameter of about 0.7 mm
(0.13 inches), an inside diameter of about 0.6 mm (0.11 inches),
and a length of about 2 m (6.5 feet).
The guide wire 402 is adapted to fit inside the lumen 420, and
"dock" with the catheter 404. To facilitate this, the distal end of
the lumen 420 has a restriction or stricture 422 for engaging the
distal end of the guide wire 402. This restriction or stricture is
preferably formed by a annular flange or ring provided on the
distal end of the catheter, although it could be some other
reduction in the lumen that can be engaged by the guide wire. The
ring can be made of tantalum.
The guide wire and catheter combination 400 can be introduced into
a body lumen, such as a blood vessel, and navigated to its desired
position by the controlled application of magnetic fields. The
application of a magnetic field allows the operator to steer the
distal end of the guide wire 402 by orienting the distal end of the
guide wire to the desired direction of travel. The guide wire 402
can be advanced using the magnetic field to pull the magnets on the
distal end or the guide wire can be advanced by pushing the
proximal end. As the guide wire 402 advances, the catheter 404 can
be advanced.
Once the distal end 418 of the catheter 404 has been placed in its
desired location, the guide wire 402 can be withdrawn through the
lumen 420, and out the proximal end 416.
As shown in FIG. 17, the guide wire 412 can be used to navigate a
biopsy tool 428 through a body lumen such as a kidney. The biopsy
tool 428 has a lumen 430 therein. The distal end of the guide wire
402 is adapted to fit into the lumen 430 and "dock" with the biopsy
tool. A magnetic field is applied to orient the magnet 408 inside
the lumen 430 of the biopsy tool 428. The biopsy tool 428 can then
be advanced, in the desired direction either by pushing the
proximal end of the guide wire 402, or pulling the distal end of
the guide wire with the magnetic field. When the biopsy tool 428
has been advanced to its desired location, the guide wire 402 can
be withdrawn.
The guide wires of either embodiment can be used to deliver
catheter or other medical devices to locations within the body
accessible via a body lumen. For example the guide wire could be
used to navigate a device for retrieval of man made objects e.g.
stents, or body made objects e.g. stones. The high degree of
articulation of the tip provides the control needed to capture and
recover such objects.
Operation
In operation, one of the guide wires 22, 40, 50, 60, 70, 90, 110,
120, 130, 150, 160, or 180 of the first embodiment and an
associated catheter or other medical device is introduced through a
natural or surgically formed opening in a body lumen. A magnetic
field is applied to orient the distal tip within the body lumen.
The magnetic field can also be used to advance the distal tip of
the guide wire, or the guide wire can be pushed to advance the
guide wire in the body lumen. As the guide wire is incrementally
advanced the catheter can be advanced over the guide wire. Once the
distal end of the catheter is in its desired position, the magnet
is removed from the catheter by pulling the guide wire to withdraw
the magnet through the lumen of the catheter.
Because the magnet on the guide wire can be removed from the
treatment site, multiple catheters can be directed in the same
general area to facilitate a medical procedure with independent
control of the catheters.
In operation, the guide wire 402 is inserted into the lumen of the
catheter 404 (or other medical device) and the guide wire and
catheter combination 400 of the second embodiment is introduced
through an opening in a natural or surgically formed opening in a
body lumen. A magnetic field is applied to orient the magnet 408 on
the proximal end of the guide wire 402, inside the catheter 404.
The guide wire and catheter are then advanced, either by applying a
magnetic field, or by pushing the distal end of the guide wire.
Once the distal end 418 of the catheter is in its desired position,
the guide wire 402 is removed from the catheter 404 by pulling the
guide wire 402 to withdraw it from the lumen 420 of the
catheter.
Once the catheter 24 or 404 is in position it can be used for the
administration of drug therapy or to perform a medical procedure or
it can be used as a guide to insert medical devices to the area
surrounding the distal end of the catheter to perform a medical
procedure.
Because the magnet on the guide wire can be removed from the
treatment site, multiple catheters can be directed in the same
general area to facilitate a medical procedure with independent
control of the catheters. Of course, the magnet could be left in
place within the catheter, if desired.
* * * * *